Paracrocodylomorpha

Last updated

Paracrocodylomorphs
Temporal range:
Early TriassicHolocene, 247–0  Ma
Poposaurus gracilis (1) flipped.jpg
Poposaurus gracilis, a poposauroid
Nile Crocodile Side View 2620px.jpg
Crocodylus niloticus, a loricatan
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Suchia
Clade: Paracrocodylomorpha
Parrish, 1993 [1]
Subtaxa

Paracrocodylomorpha is a clade of pseudosuchian archosaurs. The clade includes the diverse and unusual group Poposauroidea as well as the generally carnivorous and quadrupedal members of Loricata, including modern crocodylians. Paracrocodylomorpha was named by paleontologist J. Michael Parrish in 1993, [1] although the group is now considered to encompass more reptiles than his original definition intended. The most recent definition of Paracrocodylomorpha, as defined by Sterling Nesbitt in 2011, is "the least inclusive clade containing Poposaurus and Crocodylus niloticus (the Nile crocodile). [2] Most groups of paracrocodylomorphs became extinct at the end of the Triassic period, with the exception of the crocodylomorphs, from which crocodylians such as crocodiles and alligators evolved in the latter part of the Mesozoic.

Contents

History and definition

Parrish (1993) defined Paracrocodylomorpha as the last common ancestor of "Poposauridae" and Crocodylomorpha and all of its descendants. He believed that Poposaurus and its allies were among the closest relatives of crocodylomorphs. Therefore, his definition was intended to exclude various groups of heavily-built Triassic pseudosuchians, collectively known as "rauisuchians". Weinbaum & Hungerbühler (2007) hypothesized that the relations of Pseudosuchians were reversed to those hypothesized by Parrish. They claimed that "rauisuchians" such as Postosuchus , Batrachotomus , and Saurosuchus were closer to crocodylians than Poposaurus was. They erected a subgroup within Paracrocodylomorpha which they called Paracrocodyliformes. This subgroup contained all pseudosuchians closer to those three "rauisuchians" (as well as the Nile crocodile) rather than Poposaurus. [3]

Nesbitt (2011) introduced the most recent and common definition of Paracrocodylomorpha in his broad phylogenetic analysis. His results supported Weinbaum & Hungerbühler (2007)'s claim that "rauisuchians" were closer to crocodylians than Poposaurus was. In fact, he found that crocodylomorphs were actually descended from the "rauisuchian" group, thus rendering "Rauisuchia" a paraphyletic grade of various reptiles leading to crocodylomorphs. Moreover, the name "Paracrocodyliformes" used by Weinbaum & Hungerbühler (2007) was assigned a new name, Loricata. [2]

Ticinosuchus, the sister taxon to paracrocodylomorphs under Nesbitt (2011)'s methodologies Ticinosuchus BW.jpg
Ticinosuchus , the sister taxon to paracrocodylomorphs under Nesbitt (2011)'s methodologies

The name "Paracrocodylomorpha" was re-defined by Nesbitt in his study, reacquiring a name similar to its original usage by Parrish (1993). Nesbitt found that poposauroids formed the sister group to loricatans, and that the clade encompassing poposauroids and loricatans required a new name. Therefore, he used Paracrocodylomorpha to connect Poposaurus and Crocodylus, and all descendants of their common ancestor. Unlike Parrish's vision for the clade, Nesbitt's Paracrocodylomorpha included the "rauisuchians", which were members of Loricata. The only "rauisuchian" not found to belong to Paracrocodylomorpha with absolute confidence was the former "prestosuchid" Ticinosuchus . Nesbitt found that his most parsimonious results indicated that this genus was the sister taxon of the paracrocodylomorphs, rather than an internal component of the group. However, due to its crushed skeleton obscuring crucial anatomical details, it is also conceivable that Ticinosuchus may actually belong inside Paracrocodylomorpha pending new info. [2] This result has already been recovered by Da-Silva et al. (2019), which places Ticinosuchus as the basalmost loricatan while also sometimes having the recently described suchian Mandasuchus lie outside of the group. [4]

Description

Unambiguous synapomorphies

Under Nesbitt (2011)'s revised interpretation of the clade's components, only two unambiguous synapomorphies (derived distinguishing traits) were found for Paracrocodylomorpha. The tip of each pubis (forward-pointing hip bone) expands into a structure known as a pubic boot. In addition, metatarsal II (the foot bone which connects to the second-innermost toe) is at least as long if not longer than metatarsal IV (the foot bone which connects to the outermost toe). More basal pseudosuchians such as aetosaurs, ornithosuchids, Gracilisuchus, and Ticinosuchus lack these two traits. [2]

Ambiguous synapomorphies

'Pillar-erect' hip joints (right) may have evolved at the base of Paracrocodylomorpha, or in an earlier common ancestor with aetosaurs Sprawling and erect hip joints - horizontal.svg
'Pillar-erect' hip joints (right) may have evolved at the base of Paracrocodylomorpha, or in an earlier common ancestor with aetosaurs

Various paracrocodylomorphs share a few other derived traits, although it is not entirely clear if these features evolved precisely at the base of Paracrocodylomorpha and thus characterize the group. Some of these traits cannot be proven or disproven to exist in the crushed skeleton of Ticinosuchus. If they are present in Ticinosuchus, they evolved prior to Paracrocodylomorpha, but if not present in that genus, they can also be considered to be synapomorphies for Paracrocodylomorpha. [2]

For example, the inner face of the jaw joint possesses a spur that projects downwards and inwards in loricatans and basal poposauroids, although this trait is unknown in Ticinosuchus and lost in advanced poposauroids such as Poposaurus and shuvosaurids. A similar trait is the fact that the ilium (upper hip plate) leans outwards. This forces the acetabulum (hip socket) to face downwards, leading to a 'pillar-erect' hip posture. [5] This posture is well known in loricatans (apart from sprawling crocodylomorphs) and basal poposauroids, but it is also known in aetosaurs. Aetosaurs may have acquired this posture independently, but if not, it cannot be considered a synapomorphy of Paracrocodylomorpha. Advanced poposauroids lack an outward-leaning ilium, but also possess a specialized supraacetabular crest which forces the acetabulum to face downward, resulting in the retention of a 'pillar-erect' posture. [6] Some paracrocodylomorphs also have a pubis which contacts the ischium (rear-pointing hip bone) only slightly compared to earlier pseudosuchians. In poposauroids other than Qianosuchus and Lotosaurus , this trait is exaggerated to the point that the two bones don't even touch each other. [2]

Prestosuchus, a basal loricatan likely very similar to the ancestral paracrocodylomorph Prestosuchus-chiniquensis (2).jpg
Prestosuchus , a basal loricatan likely very similar to the ancestral paracrocodylomorph

Various paracrocodylomorphs possess a pit on the snout, between the premaxilla and maxilla bones. This pit, termed a 'subnarial foramen' was found by Nesbitt (2011) to be present only in loricatans at least as derived as Batrachotomus. [2] However, a restudy of Prestosuchus by Da-Silvia et al. (2016) showed that the pit was present in basal loricatans as well as poposauroids. They proposed that a subnarial foramen may have been an additional synapomorphy of Paracrocodylomorpha, although it is unknown in Ticinosuchus. [7]

The proximal portion of the femur (thigh bone) in some paracrocodylomorphs also possessed derived features compared to earlier taxa. Like many other archosaurs, the femoral head is tilted about 45 degrees outwards and backwards. The inner/rear face of the head possesses two large bumps (tubera), one more inward than the other. In non-paracrocodylomorph pseudosuchians, the more outward/rearward one (the posteromedial tuber) is larger, but in poposauroids and most loricatans, they are equal in size. However, Prestosuchus, one of the most basal loricatans, had a larger posteromedial tuber. Nevertheless, even more basal loricatans such as Mandasuchus had tubera of equal sizes, indicating that the situation in Prestosuchus was an anomaly. [8] The femoral head may also have possessed a straight groove on its upper side in the earliest paracrocodylomorphs. This final trait is known in poposauroids and a few loricatans more basal than Fasolasuchus , but it is also unknown in Ticinosuchus and present in Nundasuchus [9] so it may have predated Paracrocodylomorpha. [2]

Phylogeny

According to Parrish (1993), this clade was nested within Rauisuchia, a group of crurotarsans that once included only extinct Triassic forms but is now generally regarded as paraphyletic. Rauisuchia traditionally included the families Rauisuchidae and Poposauridae to the exclusion of Crocodylomorpha, but Parrish found Poposauridae more closely related to Crocodylomorpha than to Rauisuchidae. This close relationship was recognized since the 1980s. The genus Gracilisuchus was also found to be a close relative of crocodylomorphs and poposaurids but was not placed within Paracrocodylomorpha. Below is a cladogram showing the phylogenetic relationships in Parrish's 1993 study: [1]

Crurotarsi  

Ornithosuchidae Ornithosuchus BW white background.jpg

  Crocodylotarsi  

Parasuchia Smilosuchus adamanensis flipped.jpg

  Suchia  

Prestosuchidae Prestosuchus-chiniquensis (2).jpg

  Rauisuchiformes  

Aetosauria Desmatosuchus spurensis flipped.jpg

  Rauisuchia  

Rauisuchidae Rauisuchus tiradentes.jpg

Gracilisuchus Gracilisuchus BW white background.jpg

 Paracrocodylomorpha

Poposauridae Poposaurus gracilis (1) flipped.jpg

Crocodylomorpha Deinosuchus riograndensis.png

However, more recent analyses have doubted the idea that poposaurids (and by extension other poposauroids) were grouped with crocodylians to the exception of other groups. For example, a 2007 phylogenetic study by Weinbaum & Hungerbühler, found the rauisuchian families Rauisuchidae and Prestosuchidae to be more closely related to Crocodylomorpha than was Poposauridae. The authors erected the clade Paracrocodyliformes for the clade including Rauisuchidae, Prestosuchidae, and Crocodylomorpha. [3] In addition, several putative poposaurids such as Postosuchus and Teratosaurus were found to be rauisuchids. Sterling J. Nesbitt in 2011 found a similar topology, including Rauisuchidae and "Prestosuchidae" ( the latter of which he found to be polyphyletic) within Paracrocodylomorpha. The closest relative of Paracrocodylmorpha to not qualify as a member of the clade is Ticinosuchus , a large predator once considered to qualify as a prestosuchid. [2] The composition of Paracrocodylomorpha generally follows the analysis of Nesbitt (2011) in other recent studies.

Archosauria  

Avemetatarsalia Meyers grosses Konversations-Lexikon - ein Nachschlagewerk des allgemeinen Wissens (1908) (Antwerpener Breiftaube).jpg

  Pseudosuchia  

Ornithosuchidae Ornithosuchus BW white background.jpg

  Suchia  

Gracilisuchus Gracilisuchus BW white background.jpg

Turfanosuchus Turfanosuchus NT White Background.jpg

Revueltosaurus Revueltosaurus.jpg

Aetosauria Desmatosuchus spurensis flipped.jpg

Ticinosuchus Ticinosuchus BW white background.jpg

 Paracrocodylomorpha 

Poposauroidea Poposaurus gracilis (1) flipped.jpg

  Loricata  

Prestosuchus Prestosuchus-chiniquensis (2).jpg

Saurosuchus Saurosuchus BW white background.jpg

Batrachotomus Batrachotomus1DB.jpg

Fasolasuchus

Rauisuchidae

Rauisuchus Rauisuchus tiradentes.jpg

Polonosuchus Polonosuchus silesiacus (2).jpg

Postosuchus Postosuchus kirkpatricki flipped.jpg

Crocodylomorpha Deinosuchus riograndensis.png

Related Research Articles

<span class="mw-page-title-main">Rauisuchia</span> Informal group of Triassic archosaurs with pillar-erect posture

"Rauisuchia" is a paraphyletic group of mostly large and carnivorous Triassic archosaurs. Rauisuchians are a category of archosaurs within a larger group called Pseudosuchia, which encompasses all archosaurs more closely related to crocodilians than to birds and other dinosaurs. First named in the 1940s, Rauisuchia was a name exclusive to Triassic archosaurs which were generally large, carnivorous, and quadrupedal with a pillar-erect hip posture, though exceptions exist for all of these traits. Rauisuchians, as a traditional taxonomic group, were considered distinct from other Triassic archosaur groups such as early dinosaurs, phytosaurs, aetosaurs, and crocodylomorphs.

<span class="mw-page-title-main">Poposauridae</span> Extinct family of reptiles

Poposauridae is a family of large carnivorous archosaurs which lived alongside dinosaurs during the Late Triassic. They were around 2.5 to 5 metres long. Poposaurids are known from fossil remains from North and South America. While originally believed to be theropod dinosaurs, cladistic analysis has shown them to be more closely related to crocodiles.

<i>Gracilisuchus</i> Genus of fossil reptiles

Gracilisuchus is an extinct genus of tiny pseudosuchian from the Late Triassic of Argentina. It contains a single species, G. stipanicicorum, which is placed in the clade Suchia, close to the ancestry of crocodylomorphs. Both the genus and the species were first described by Alfred Romer in 1972.

<span class="mw-page-title-main">Pseudosuchia</span> Clade of reptiles

Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Despite Pseudosuchia meaning "false crocodiles", the name is a misnomer as true crocodilians are now defined as a subset of the group.

<span class="mw-page-title-main">Rauisuchidae</span> Extinct family of reptiles

Rauisuchidae is a group of large predatory Triassic archosaurs. Some disagreement exists over which genera should be included in the Rauisuchidae and which should be in the related Prestosuchidae and Poposauridae, and indeed whether these should even be thought of as separate valid families. Rauisuchids occurred throughout much of the Triassic, and may have first occurred in the Early Triassic if some archosaurian taxa such as Scythosuchus and Tsylmosuchus are considered to be within the family.

<span class="mw-page-title-main">Prestosuchidae</span> Extinct family of reptiles

Prestosuchidae is a polyphyletic grouping of carnivorous archosaurs that lived during the Triassic. They were large active terrestrial apex predators, ranging from around 2.5 to 7 metres in length. They succeeded the Erythrosuchidae as the largest archosaurs of their time. While resembling erythrosuchids in size and some features of the skull and skeleton, they were more advanced in their erect posture and crocodile-like ankle, indicating more efficient gait. "Prestosuchids" flourished throughout the whole of the middle, and the early part of the late Triassic, and fossils are so far known from Europe, India, Africa (Tanzania), Argentina, and Paleorrota in Brazil. However, for a long time experts disagree regarding the phylogenetic relationships of the group, what genera should be included, and whether indeed the "Prestosuchidae" constitute a distinct family.

<i>Poposaurus</i> Extinct genus of Archosaur

Poposaurus is an extinct genus of pseudosuchian archosaur from the Late Triassic of the southwestern United States. It belongs to the clade Poposauroidea, an unusual group of Triassic pseudosuchians that includes sail-backed, beaked, and aquatic forms. Fossils have been found in Wyoming, Utah, Arizona, and Texas. Except for the skull, most parts of the skeleton are known. The type species, P. gracilis, was described and named by Maurice Goldsmith Mehl in 1915. A second species, P. langstoni, was originally the type species of the genus Lythrosuchus. Since it was first described, Poposaurus has been variously classified as a dinosaur, a phytosaur, and a "rauisuchian".

<i>Batrachotomus</i> Genus of reptiles

Batrachotomus is a genus of prehistoric archosaur. Fossils of this animal have been found in southern Germany and dated from the Ladinian stage of the Middle Triassic period, around 242 to 237 million years ago. Batrachotomus was described by palaeontologist David J. Gower 22 years after its discovery.

<i>Luperosuchus</i> Extinct genus of reptiles

Luperosuchus is an extinct genus of loricatan pseudosuchian reptile which contains only a single species, Luperosuchus fractus. It is known from the Chañares Formation of Argentina, within strata belonging to the latest Ladinian stage of the late Middle Triassic, or the earliest Carnian of the Late Triassic. Luperosuchus was one of the largest carnivores of the Chañares Formation, although its remains are fragmentary and primarily represented by a skull with similarities to Prestosuchus and Saurosuchus.

Yarasuchus is an extinct genus of avemetatarsalian archosaur that lived during the Anisian stage of the Middle Triassic of India. The genus was named and described in 2005 from a collection of disarticulated but fairly complete fossil material found from the Middle Triassic Yerrapalli Formation. The material is thought to be from two individuals, possibly three, with one being much more complete and articulated than the other. The type and only species is Y. deccanensis. Yarasuchus was a quadruped roughly 2–2.5 metres (6.6–8.2 ft) long, with an elongated neck and tall spines on its vertebrae. Unlike other quadrupedal Triassic reptiles, the limbs and shoulders of Yarasuchus were slender, and more like those of ornithodirans.

Arganasuchus is an extinct genus of "rauisuchian" (loricatan) archosaur. It is known from a single species, Arganasuchus dutuiti. Fossils of this genus have been found in Upper Triassic rocks of the Argana Basin, Morocco. Though its remains were initially referred to Ticinosuchus when discovered during the 1970s, in 2007 it was identified as a distinct genus with unique features of the pubis and maxilla. Arganasuchus also had several anatomical details in common with Batrachotomus, Fasolasuchus, and Postosuchus, though its relations with other loricatans remains unresolved. Arganasuchus is considered a carnivore due to its large, knife-shaped teeth.

<i>Fasolasuchus</i> Extinct genus of reptiles

Fasolasuchus is an extinct genus of loricatan. Fossils have been found in the Los Colorados Formation of the Ischigualasto-Villa Unión Basin in northwestern Argentina that date back to the Norian stage of the Late Triassic, making it one of the last "rauisuchians" to have existed before the order became extinct at the end of the Triassic.

<i>Heptasuchus</i> Extinct genus of reptiles

Heptasuchus is an extinct genus of loricatan pseudosuchian known from the Middle or Late Triassic upper Chugwater Group of Wyoming, United States. It contains a single species, Heptasuchus clarki, the first formally recognized "rauisuchian" or loricatan pseudosuchian from North America.

<i>Mandasuchus</i> Extinct genus of reptiles

Mandasuchus is an extinct genus of loricatan pseudosuchian from the Manda Formation of Tanzania, which dates back to the Anisian stage of the Middle Triassic. Although this genus was first mentioned by Alan Charig in 1956, a formal description was not published until 2018.

<span class="mw-page-title-main">Suchia</span> Clade of reptiles

Suchia is a clade of archosaurs containing the majority of pseudosuchians. It was defined as the least inclusive clade containing Aetosaurus ferratus, Rauisuchus tiradentes, Prestosuchus chiniquensis, and Crocodylus niloticus by Nesbitt (2011). Generally the only pseudosuchian group which is omitted from Suchia is the family Ornithosuchidae, although at least one analysis classifies ornithosuchids as close relatives of erpetosuchids and aetosaurs. Phytosaurs are also excluded from Suchia, although it is not certain whether they qualify as pseudosuchians in the first place.

<span class="mw-page-title-main">Loricata</span> Extinct clade of reptiles

Loricata is a clade of archosaur reptiles that includes crocodilians and some of their Triassic relatives, such as Postosuchus and Prestosuchus. More specifically, Loricata includes Crocodylomorpha and most "rauisuchians", a paraphyletic grade of large terrestrial pseudosuchians which were alive in the Triassic period and ancestral to crocodylomorphs.

<span class="mw-page-title-main">Poposauroidea</span> Extinct clade of reptiles

Poposauroidea is a clade of advanced pseudosuchians. It includes poposaurids, shuvosaurids, ctenosauriscids, and other unusual pseudosuchians such as Qianosuchus and Lotosaurus. It excludes most large predatory quadrupedal "rauisuchians" such as rauisuchids and "prestosuchids". Those reptiles are now allied with crocodylomorphs in a clade known as Loricata, which is the sister taxon to the poposauroids in the clade Paracrocodylomorpha. Although it was first formally defined in 2007, the name "Poposauroidea" has been used for many years. The group has been referred to as Poposauridae by some authors, although this name is often used more narrowly to refer to the family that includes Poposaurus and its close relatives.

<i>Diandongosuchus</i> Extinct genus of reptiles

Diandongosuchus is an extinct genus of archosauriform reptile, possibly a member of the Phytosauria, known from the Middle Triassic of China. The type species Diandongosuchus fuyuanensis was named in 2012 from the Zhuganpo Formation of Yunnan Province. It is a marine species that shows similarities with another Chinese Triassic species called Qianosuchus mixtus, although it has fewer adaptations toward marine life. It was originally classified as the basal-most member of the pseudosuchian clade Poposauroidea. However, a subsequent study conducted by Stocker et al. indicated it to be the basalmost known phytosaur instead.

Nundasuchus is an extinct genus of crurotarsan, possibly a suchian archosaur related to Paracrocodylomorpha. Remains of this genus are known from the Middle Triassic Manda beds of southwestern Tanzania. It contains a single species, Nundasuchus songeaensis, known from a single partially complete skeleton, including vertebrae, limb elements, osteoderms, and skull fragments.

<i>Mambawakale</i> Extinct genus of reptiles

Mambawakale is a genus of large sized basal paracrocodylomorph, possibly a poposauroid, from the Manda Beds of Tanzania. It was informally named Pallisteria before being officially published under its current name almost 60 years after its discovery. It contains a single species, Mambawakale ruhuhu.

References

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  2. 1 2 3 4 5 6 7 8 9 Nesbitt, Sterling J. (2011). "The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades". Bulletin of the American Museum of Natural History . 352: 1–292. doi: 10.1206/352.1 . hdl:2246/6112. S2CID   83493714.
  3. 1 2 Weinbaum, Jonathan C.; Hungerbühler, Axel (June 2007). "A revision of Poposaurus gracilis (Archosauria: Suchia) based on two new specimens from the Late Triassic of the southwestern U.S.A." Paläontologische Zeitschrift . 81 (2): 131–145. Bibcode:2007PalZ...81..131W. doi:10.1007/BF02988388. S2CID   84822632.
  4. Lúcio Roberto-Da-Silva; Rodrigo Temp Müller; Marco Aurélio Gallo de França; Sérgio Furtado Cabreira; Sérgio Dias-Da-Silva (2018). "An impressive skeleton of the giant top predator Prestosuchus chiniquensis (Pseudosuchia: Loricata) from the Triassic of Southern Brazil, with phylogenetic remarks". Historical Biology: An International Journal of Paleobiology. 32 (7): 1–20. doi:10.1080/08912963.2018.1559841. S2CID   92517047.
  5. Juul, Lars (1994). "The phylogeny of basal archosaurs" (PDF). Palaeontologia Africana. 31: 1–38. ISSN   0078-8554.
  6. Schachner, E.R.; Manning, P.L.; Dodson, P. (2011). "Pelvic and hindlimb myology of the basal archosaur Poposaurus gracilis (archosauria: Poposauroidea)". Journal of Morphology. 272 (12): 1464–1491. doi:10.1002/jmor.10997. PMID   21800358. S2CID   4651357.
  7. Roberto-Da-Silva, Lúcio; França, Marco a. G.; Cabreira, Sérgio F.; Müller, Rodrigo T.; Dias-Da-Silva, Sérgio; Roberto-Da-Silva, Lúcio; França, Marco a. G.; Cabreira, Sérgio F.; Müller, Rodrigo T. (November 2016). "On the presence of the subnarial foramen in Prestosuchus chiniquensis (Pseudosuchia: Loricata) with remarks on its phylogenetic distribution". Anais da Academia Brasileira de Ciências. 88 (3): 1309–1323. doi: 10.1590/0001-3765201620150456 . ISSN   0001-3765. PMID   27508994.
  8. Richard J. Butler; Sterling J. Nesbitt; Alan J. Charig; David J. Gower; Paul M. Barrett (2018). "Mandasuchus tanyauchen, gen. et sp. nov., a pseudosuchian archosaur from the Manda Beds (?Middle Triassic) of Tanzania" (PDF). Journal of Vertebrate Paleontology. 37 (Supplement to No. 6): 96–121. Bibcode:2017JVPal..37S..96B. doi:10.1080/02724634.2017.1343728. S2CID   90164051.
  9. Nesbitt, Sterling J.; Sidor, Christian A.; Angielczyk, Kenneth D.; Smith, Roger M. H.; Tsuji, Linda A. (2014-09-19). "A new archosaur from the Manda beds (Anisian, Middle Triassic) of southern Tanzania and its implications for character state optimizations at Archosauria and Pseudosuchia". Journal of Vertebrate Paleontology. 34 (6): 1357–1382. Bibcode:2014JVPal..34.1357N. doi:10.1080/02724634.2014.859622. ISSN   0272-4634. S2CID   129558756.